Since the global climate change and environmental consciousness have attracted tremendous amount of attention, most industries related to human lives have developed green technologies, among which the energy technologies take the lead. The windpower generator is one of the most important energy technologies because windpower is clean, low greenhouse gas emission, and renewable. Therefore, most of the western countries have launched the development and application of the windpower generator.
The windpower generating system can be divided into the horizontal-axis and the vertical-axis power generating systems. The horizontal-axis power generating system has a fan with a horizontal rotation axis, while the vertical-axis power generating system has a fan with a vertical rotation axis. According to some reports, the vertical-axis windpower generating system has advantages over the conventional horizontal-axis windpower generating system such as advanced machining design, low manufacturing cost, low threshold wind speed, low noise and less light pollution. Therefore, it has great potential in commercial applications.
Referring to FIG. 1, which is a 3-D diagram of a dual-layer vertical-axis fan module disclosed in U.S. Pub. No. 20080095631. The vertical-axis fan module comprises two fan units. Each of the fan units comprising three twisted blades disposed therein. On each of the top and bottom ends, there is provided a connecting plate coupled to both ends of the blade. The blade module further comprises a rotation axle penetrating through the center of the connecting plate.
Moreover, as disclosed in U.S. Pub. No. 2008253889, a fan module with a dual-layer fan, as shown in FIG. 2, comprises a plurality of fan units. Each of the fan units comprises respectively three blades. On both ends of the three blades, there are provided respectively a connecting unit. Between two connecting units, there are a plurality of supporting arms connected to a rotation axle.